1. Field of the Invention
The present invention relates to a method of modeling based on rounding and inverse-rounding of a 3-dimensional object, and, also, relates to a computer-readable memory medium having programs recorded therein for implementing the method of modeling.
2. Description of the Related Art
As we all know, speed at which computers can manipulate information has been increasing at a significant rate, and an ever greater data-processing power has been applied in many areas of technology. Among these, 3-dimensional CG (computer graphics) has become such a familiar technological area as can be found everywhere as in movies, televisions, games, etc. Recent CG images are created by using smooth curved surfaces, successfully representing such complex figures as human bodies and animal bodies. In video images using such a CG technique, not only a generation of 3-dimensional objects but also free deformation of these 3-dimensional objects is utilized, thereby adequately representing movement of these figures. When such a modeling scheme based on smooth curved surfaces is to be used, it should be insured that flexibly manipulable deformation is possible.
As a scheme to achieve flexibly manipulable deformation, a free-form-deform scheme (FFD) is well known. The FFD refers to a concept for representing global deformation of a shape such as extension, bending, and contortion in the 3-dimensional CG. In the FFD, a control grid is generated by arranging a plurality of control points at grid points to surround a 3-dimensional object, and, then, the generated control grid is deformed to change the shape of an interior parameter space. The deformation of the interior parameter space is mapped to the 3-dimensional object. Various researches have been done on this scheme, and the FFD has been employed in a large number of CG-animation generation systems.
The FFD scheme, however, suffers a limitation in flexibility of deformation control depending on the shapes of 3-dimensional objects. Against this background, other schemes have been presented with an aim of generating a control grid reflecting a shape of a 3-dimensional object so as to enhance the flexibility of deformation control. There are other problems, however, such as difficulties to define a control grid, a high computation cost, etc., which remain to be overcome.
Accordingly, there is a need for a method of modeling which achieves flexible deformation without incurring a high computation cost.